Process for making angularly bent drinking tubes



April 13, 1943. I I s. T. MALTBY 2,316,700

V PROCESS FOR MAKING ANGULARLY BENT DRINKING TUBES' Filed April 11, 1940 fji l- Snnentor attorneg Patented Apr. 13, 1943 asixzoo PROCESS FOR MAKING ANGULARLY BENT DRINKING TUBES Sidney T. Maltby, Washington, D. Stone Straw Corporation, Washington,

0., assignor to D. 0., a

corporation of New Jersey Application April 11, 1940, Serial No. 329,163

4 Claims.

This invention relates to processes for making angularly bent drinking tubes, and more particularly to the formation of such a tube from straight tubular stock, softened in a region intermediate its length and bent to angular shape,

while supported internally to obviate buckling and collapse at the point of bend; all as will be described more fully hereinafter, and as claimed.

Angularly bent drinking tubes have heretofore been formed from straight'lengths of glass tubing bent to shape over an open flame. These have found extensive use in such institutions as hospitals where the patients must be served in reclining position, but their use in the home and at soda fountains where they would also fill a needhas been deterred, both because of their cost as compared to paper and amorphous cellulose straws or sippers, and because they cannot readily be cleaned and sterilized for re-use. From the standpoint of sanitation, the artificial straw is manifestly superior to a glass tube, for it may be disposed of afte a single use. Moreover, a glass tube possesses the disadvantage that it is likely to break in the mouth of the user, causing severe injury.

The present invention has as one of its objects to produce angularly bent drinking tubes which are safe, sanitary, and so inexpensive that they may be replaced as frequently as desired.

A further object is to produce an angularly bent drinking tube of a material which softens under heat, or by a solvent, and which when being bent is supported internally to prevent buckling and collapse of the wall at the point of bend, so that the resulting tube is of substantially uniform bore throughout.

Other and further objects will be apparent from the following description and drawing wherein, by way of illustration, one form of my process is illustrated in its various steps, with mechanism for performing it.

Figure 1 is a side view of a straight length of tubing preparatory to bending.

Figure 2 shows the tube in position on a nozzle through which fluid is admitted to its interior.

Figure 3 shows the method of closing the projecting open end of the tube in process.

Figure 4 shows the softened tube in position over a heater, and bent to angular shape.

Figure 5 shows the completed tube stripped from the fluid nozzle.

Figure 6 is a partly diagrammatic plan view of one form of a machine for performing the successive steps of a preferred form of process.

Referring more particularly to the drawing,

and first to Figure 6, wherein is illustrated the series of steps as they are performed in succession in a machine adapted therefor, a tube ll), of cellulose acetate or other suitable material which is capable of softening'under heat, is delivered from a hopper shown in dotted lines and is first mounted on a nozzle I I which communicates with a source of air under pressure. This may conveniently be performed by a tamper l2 which forces the tube onto the nozzle. 7

Next, the projecting end of the tube is passed in proximity to a heater l3 to soften it, whereupon it is pinched closed by a'hammer and anvil l4, and is thus sealed. If the tube is made of cellulose acetate, or similar material which has the property of shrinking under heat, it need not be pinched closed, since the fusing and shrinking of the end will close it sufficiently to maintain internal pressure for keeping its wall distended during bending. v r j Following the closing, or substantial closing, of the projecting end of the tube it is exposed in an intermediate region to heat from a heater [5, whereupon it softens, and the projecting end drops onto a stop or' guard I6 which limits the ex= tent of its bending.

While the tube is in softened condition air is admitted through the nozzle II to the interior thereof. The internal pressure affords support which prevents the tube wall from collapsing or buckling at the point of bend.

Finally, the tube now cooled is clipped by a trimmer l! to remove the sealed end, and the completed tube is stripped from its associated nozzle II for delivery.

In place of air, an inert gas may be blown the tube to support it during bending.

into

A modification of the preferred process com-.

prises supplying liquid to the interior of the tubes in process, in which case their ends may either be sealed, as when air is used, or the tubes may be supported in a position approaching the vertical, with their open ends above the region of bend, whereby the water or other liquid constituting the core will support the wall of the tube and prevent buckling when it softens and bends.

In another modification, a solvent softened tube is employed, wherein the solvent is applied to a region intermediate its ends while at the same time the tube is internally supported to prevent its collapse during bending and until it has reset and hardened.

In still another modification of my process, the projecting end of the tube is left open, and

air or inert gas is blown through it under pressure suficient to hold its wall distended. In the practice of this form of process the tendency of the air blast to prevent bending may be overcome by furnishing means for deflecting the end of the softened tube to bend it at an angle to the remaining portion.

A further modification of my process comprises filling the tube with low melting point material, such for example as some of the alloys, used in fire extinguisher sprinkler heads, which will melt at a temperature below that at which the tube material softens, and which in molten conditions forms a core for the tube. After the tube has been bent and has cooled and set, it is passed through a zone of heat sufilcient to melt out the core without, however, softening the tube to a degree which will distort the finished product. The molten core material is then collected for re-use.

Another modification of my process consists in sealing a tube of heat softened material at both ends to entrap therein an expansible fluid, which may be air, an inert gas, or a liquid. The tube is then heated and softened in the region of bend. Next, it is bent to the desired angular shape, being supported during such bending and prevented from buckling by the pressure of the entrapped and expanded fluid within it. Finally, the sealed ends of the shaped tube are clipped oiT.

From the foregoing it will be apparent that my invention provides processes for forming bent tubes of substantially uniform diameter throughout by reason of the fact that internal support is afiorded them while they are being bent to final shape and they are therefore held against buckling and collapse while they are being bent.

What I claim as my invention, and desire to secure by Letters Patent, is:

1. The process of forming angularly bent drinking tubes which comprises mounting a straight tube on a support to project beyond the same, softening the material of said tube in a restricted region within the projecting portion of said tube while supporting the same internally by fluid pressure to prevent collapse, and permitting the projecting portion of said tube to bend in its softened region while so internally supported.

2. The process of forming angularly bent drinking tubes which comprises mounting a straight tube on a support to project beyond the same, softening the projecting portion in a restricted region, subjecting the interior of said tube to air pressure to support the same against collapse in its softened region, and permitting the tube to bend in such softened region until its projecting end comes to rest on a stop which limits the angularity of bend.

3. The process of forming angularly bent drinking tubes which comprises mounting a straight tube of heat softenable material on a support to project beyond the same for a portion of its length, heating a restricted region of such projecting portion of the tube, subjecting the interior of the tube to air pressure to support the same internally against collapse in its softened region, and permitting the tube to bend in such softened region until the projecting end of the tube comes to rest on a stop which limits the angularity of bend.

4. The process of forming uniformly angularly bent drinking tubes which comprises positioning straight lengths of tube on fluid injector means, injecting fluid under pressure into said tubes. heating each tube in a restricted region within the projecting portion of said tube while internally supporting the same against collapse in its heat softened region by the injected fluid. but permitting such softened region to bend to a desired degree of angularity.

SIDNEY T. MALTBY. 

